I wanted to upgrade my computer sound card in preparation for higher impedance phones and eventually a desktop amp. This more than does the trick and improved onboard sound more than I'd expected.

The con about it needing a good power source isn't an argument against it. It turned out that my computer (Vostro 420, 2009) didn't have an extra power connection for the card so I ended up upgrading my power source as well.

Note: I'm from Sweden so if the wording or sentence structure is a bit off, I blame the Swedish educational system!!

Introduction

The ASUS Xonar Essence STX is a two channel soundcard with a built in amplifier and it is a great entry into hi-fi and head-fi, it has a good set of features and handles most games very well, at least with the newer drivers. The card has a good DAC-chip that leads into two I/V stage Op-Amps and then on to either the headphone amplifier chip, called a Hi-Z amplifier, or to the buffer stage Op-Amp. There is also a decent mic/line in for recording. The card takes its power directly from the PSU and therefore gets a very clean and strong power supply, at least if the PSU is good. The software has pretty good features and the interface is pretty self-explanatory for the most part.

Op-Amps

After getting this card I started reading the already massive thread started by ROBSCIX on this site, and soon enough I wanted to try to see what this card really could do. The sound with original chip Op-Amps was somewhat on the warm side and lacks a little something in detail but it is a good sound non the less. After reading 70+ pages of the gargantuan thread I came to the decision that the greatest improvement would come from upgrading to discreet Op-Amps from Audio-GD. After consulting some reviews and exchanging a few PMs with ROBSCIX I decided on OPA Earth for I/V and OPA Sun for buffer. This improved the sound through my loudspeakers with better positioning, better bass quality and clearer transients. The sound through the headphone-out became slightly more neutral, and the level of detail improved but not to the same extent as through the line-out.

The Headphone Amp

I do not have much experience with headphones, and my purchase of the K701s was a bit poorly researched, I just read some very positive reviews and comparisons but I failed to realize that it needs a good amp to sound as it should. Now I've never heard the from anything other than my amplifiers head-out and through the STX, and in that comparison the sound-card wins hands down. From what I've read about the K701 my impressions with the STX as source echoes what most people say: big soundstage, crystal clear highs, great midrange and weak bass on some types of music, especially rock/pop. The volume level is no problem achieving, with Replay-Gain on in Foobar, regular listening volume is at 60% on the low gain setting.

I've tried some of my other headphones through the head-out on the front of my computer, and it is very difficult to use IEMs such as my JVC-FX500 as the volume has to be set to 2-4% and at that level the cable leading from the soundcard to the front picks up some interference from hard drives and fans. Amping my vintage 600 ohm AKG K140 is no problem at all, the soundcard drives them loud and clear on medium gain.

Conclusion

This is a very good DAC and a pretty good entry-level headphone amplifier that costs as much as either would if they were external. The fact that it is from a big company such as ASUS means that the cost is cut by their ability to buy in bulk.

I can certainly recommend this card as a great entry to the world of hi-fi if you are using the line out from your stationary computer or when building a new one. The possibility to tinker with Op-Amps should also interest those who can't leave well enough alone...

I needed a lot of time to make the decision to purchase this card. During January 2010 I pondered if it actually would be an update simply because I already owned two interfaces: Creative X-FI ExtremeMusic and an E-MU 0202 USB. Furthermore, for my Sennheiser HD-600 I already had a headphone amp, a Corda Arietta, connected to the E-MU with the very good Audioquest King Cobra.

But then I heard the X-Fi with my headphones for the first time and was so appalled that I ordered the ASUS Xonar Essence. When it arrived I marveled at the design and the built quality. It looks nice, it feels nice. I subsequently ran into some installation problems (having chosen the wrong slot on my motherboard) but after sorting them out I could enjoy this little beauty.

What can I say? One word only: invisible. I don´t know how people come up with description like "it´s warm" or "it´s on the cold side" because in my opinion both are untrue. This card simply is invisible which is exactly what it´s supposed to be. Before I heard the Essence I was perfectly allright with using the combination of my E-MU and the Corda Arietta. I thought that they were neutral and dynamic. Well, I was wrong because the E-MU sounds a bit muddy with a slightly instable soundstage and the Corda Arietta steals away the lowest (below 50 Hz) and the highest frequencies (above 15 kHz - yes I can still hear them) and does some funny tiny erros in between.

The ASUS Xonar Essence sounds different because it has no own sound. It just seems to pass the music along to the integrated headphone amp and on its way the music is neither coloured nor changed. Result: some recordings I formerly perceived as good sounding now sounded like crap while for example some muffled TELARC recordings now had sparkle and detail. The Xonar Essence will point out every error in the music, it for sure is not on the forgiving side. BUT: if a recording sounds warm & cozy the ASUS will sound the same, warm & cozy. Room, soundstage, dynamic - everything is flawless. It´s as if the card is stepping into the background only to reveal the true face of the music it plays.

In comparison the combination of E-MU 0202 USB & Corda Arietta sounds awfully unbalanced and coloured. It smears away the differences between recordings, replacing them with its own sound signature - something the ASUS never does.

But oh... here comes the problem with its driver. In short, it´s crap. ASIO doesn´t work properly and ASUS doesn´t seem to be capable to produce a functioning driver. It had to come up to an ASUS forum user to provide a functioning driver. Thank God, now it can even play 88.200 and 176.000 material without resampling.

Another problem: the input applies some soft dynamic compression in order to prevent the A/D converter from clipping. Strange, isn´t the ASUS aimed at audiophiles? Because they would use a compressor after the recording process (only if they know how to operate something like that of course) and only if they choose so. But no, the ASUS has a built-in permanent compressor for the line-in which kicks in at -3dB (don´t try to lower the recording volume, the compressor sits on the hardware side).

A third problem: the card is sometimes presented by ASUS as a music production tool when in fact it isn´t capable of that. Reason: the input (besides applying compression) lags for roughly one second. Connect a keyboard to the input and press a key, the sound will arrive one second later on the headphone or line-out of the card. It doesn´t matter if you use ASIO, DirectSound, Dolby Headphone etc., the lag is always there. However, the audio quality of the input mirrors the quality of the output - it´s perfect.

Back to the sound... before I forget, I connected my Corda Arietta to the ASUS. Now the invisible sound was gone, the Corda amplifies with its own sound signature - and I don´t mean something like "more bass" or so. No, the Corda simply presents music differently with less resolution, less dynamic, less soundstage, less everything. I therefore conclude that the headphone amp inside the card is fairly good.

So what do you get? You´ll get a soundcard that´ll sound perfect at its line-out and with headphones but you´ll also get an awfully bad driver and a lagging & compressing input. You have to choose if you can live with the obstacles. If you can, you will have a tool that beats everything at its price range, something that reaches sonically towards unexpected territory: Studio Quality High End.

its been over an year since I got this sound card & I have never regretted the decision. It has played game with everything I have thrown at it- D1001, HD580, DT880 600 ohm & even my orthos. The DAC section is superior to my Marantz AVR & so is the headphone out.

Pros: Excellent Sound...no noise in quiet parts of songs, no cracks of music,

Cons: Wish had more extension out of box, but thats what opamps are for

Wish I had something to compare to. Had an audigy 2 for years and thought extension was better in treble. But Audigy 2 does not have a headphone amp and cannot push the HD650 properly. Not even sure it can push the AKG Q701. The HD600 with the audigy 2 are fantastic since HD600 does not need a headphone amp. I am a pretend to be audiophile since I have a limited budget.

Althought I do have tons of headphones: I ripped all music to wav file using EAC. I feel at times I need a headphone tube amp to improve sound. When I tested my STX against a Sony 400 disc CDplayer to receiver, both sounded exactly the same. So I stuck with the STX and ripped the CD collection to WAV.

Pros: Makes good headphones even better, great sound quality, more than doubles my volume.

Cons: initial driver problems, installation tricky.

Bought Sony MDR XB1000s almost a year ago and they've been great. A mate of mine bought a soundcard and reckons it made a big difference and convinced me to buy one. I read into reviews, and they said that this was a good card for headphones, and they are bang on. It always felt like there was something missing when i first listened to my MDRs, and i kinda felt ripped off after upgrading from MDR XB700s but this card truly justifies the upgrade. I have a modern motherboard ( MSI GD65 8D) and the audio quality increase this card gives over my mobo soundcard is staggering. Max volume increase this card gives is just crazy. HQ audio is completely flawless; no signs of clipping even at max volumes. First impressions were amazing, and it still continues to amaze me.

Installation for me was a hassle; power supply really has to be jammed in there for it to work and when it eventually did, the drivers gave me the ****s (I am running windows 8, maybe compatibility issues) and telling me to make sure the card is properly installed etc etc. but after trying a few downloaded versions from asus website, it finally worked.

However, the better the audio equipment you have, the more difference you will notice. I use my Astro A40s for teamspeak/skype and my Sonys for me-time, and the difference I find is MUCH greater on the Sonys than it is on the A40s

To sum this up, best $170 I have spent on this computer. 100% reccommend it for people who truly appreciate music and have a good pair of headphones.

I don't really have anything to compare this to, since this is my first non-board soundcard (some might say I took quite a leap) To be honest, I wasn't even expecting that much of a difference on the price, since I'm used to seeing components paying way more, but the quality of the STX really blows me away! The headphone amp is something that could be better, my only other amp is a measly Pro-Ject headbox S, which performs pretty close to the xonar, although being slightly warmer and not as detailed, also I don't really like how it sounds on your general every day 32 ohm gaming headsets, or my 55 ohm akg k121's. The Xonar is a great sound processor though, in fact it's so detailed that it made me realize that I need a better speaker amplifier to keep up with it :P

TL;DR Great (value) DAC, decent head amp for 250ohm or above headphones

I originally purchased this audio card for an Asus® CM1630-06 previously upgraded with the same vendor's EAH6850DC/2DIS/1GD5 PCI-Express x16 video card plus an Antec® TruePower™ 750 Blue for sufficient video performance for podcasts and similar live over-the-Web activities at UStream® Television. Even with the bone-stock JRC2114D dual operational amplifiers in the I-V and National Semiconductor®/Texas Instruments® LM4562N in the line-level buffer position, this card is plenty accurate and has room for further tuning. I found that the Essence™ has one of the lowest noise floors of any card on the market, almost certainly due to its conservative, radio-grade shielding approach; the EAH6850DC in the next slot (literally) added negligible additional noise. The main outputs are two RCA jacks (2 Speakers) and one 1/4" (6.3mm) jack (Headphone); the internal headphone amplifier, a Texas Instruments® TP6120A2 dual power amp, has three gain settings for different headphone impedances and sensitivities. The on-board digital-audio output, which can handle RCA coaxial and 3.5mm optical, can transmit PCM or Dolby® Digital Live to an external DAC, receiver, &c. The Unified XONAR® Software by Brainbit, Release 1.53 (C-Media CMI-8788 Driver 7.12.8.1795), runs stably on most Windows boxes; I have yet to test the Virtuoso driver from the Advanced LinUX Sound Architecture Project (LinUX Kernels 3.0-up) with either the Essence™ ST or STX.

The one downside I encountered is apparently due to a core software issue inside Microsoft® Windows® 6.1 and 7.0 with Service Pack 1, viz., an issue with the resampling DLL in the audio stack that affects other audio chips besides the AV-100 and related C-Media® chipsets (see "Xonar Essense stx Random LOUD high pitched Ringing Noise?"); an updated set of Audio Drivers C:\Windows\Sys*\WDMAud.drv has been released as part of a hotfix for Windows® Se7en™ 7.0.8001 and Windows® Server 2008 Release 2 6.1.7601. As of 26 January 2013 I do not know whether this issue has been resolved for Windows® 8.0.10000 and Windows Server 2012 8.0.10000 (MultiProcessor Kernel 6.2.9200).

Users in need of an XLR-ready audio card who have relatively RF-quiet systems may be better served by the Auzentech® X-Meridian® 7.1 2G (C-Media® CMI8788) or X-Fi® Home Theater HD™ (Creative® CA20K2), both of which use an Auzentech-exclusive microphone preamplifier to take input from balanced dynamic microphones widely used for recording studios and live sound.

No Sound in games? Solution: change from 8ch audio to 6ch, If still persists, change windows audio settings to 16bit 44.1kHz

How To:

Advice on installation, customization, and anything else.

Note: ASIO4All is not proper ASIO, its just a wrapper, rather use WASAPI.

Basic recommended setup (for Music):

Install latest Uni Xonar drivers, not the standard Asus ones.

Set windows output to 2channel 24bit/48kHz (for digital volume control, and to avoid the 44.1kHz bug, and it measures the best on the lower settings.) Right click the Sound/Speaker icon in the taskbar, go to "Playback Devices", double click on "Speakers/Headphones", go to the "Advanced" Tab, set the default format to 24bit, 48kHz. Set player volume to 100% and control volume via system volume (76% maximum to avoid dynamic limiting). This SHOULD only matter in WASAPI, But is sometimes not the case, so to be safe do it anyway.

Use a proper music player (MusicBee/ Foobar2000) since it matters, refer to the Foobar2000 specific settings.

Set MusicBee or foobar2000 to use ASIO drivers and set to 24 bit, and tell the player to upsample the audio to 48kHz. Player volume should = system volume, if not, set player volume to 100% and control via system volume (76% maximum to avoid dynamic limiting).

If ASIO gives errors use WASAPI drivers, tell the player to upsample to 48kHz.

If your using WASAPI open the Xonar centre and click the "HF" button, to turn on Hi-Fi, which disables all processing